Tuner for radio receiving sets



May 20, 1941,

I We 5??? A. S. WELLS ETAL TUNER FOR RADIO RECEIVING SETS Filed Mar chl,1937 5 Sheets-Sheet 1 v May 20, 1941. A. s. WELLS ETAL 2,242,768

TUNER FOR RADIO macmvme SETS Filed Margh 1, 1937 5 Shee ts-Sheet 2 May20, 1941. A. s. WELLS E 2,242,768

TUNER FOR RADIO RECEIVING SETS Filed March 1, 1937 5 Sheets-Sheet 5 y1941. A. s; WELLS AL I TUNER FOR RADIQ RECEIVING SETS Filed March 1,1937 5 Sheets-Sheet 4 May 20, .1941. A, s. WELLS Em 2 42 7 8 TUNER FORRADIO RECEIVING SETS Filed March 1, 1937 5 Sheets-Sheet 5 zzzwwfez III!"Patented May 2!), 1941 UNETED STAT TUNER FOR. RADIO RECEIVING SETSApplication March 1, 1937, Serial No. 128,378

6 Claims. (Cl. 250-20) An object of this invention is to provide animproved form of tuning device for radio receiving sets which can beoperated to tune in a desired station by a single continuous operationof the operators finger.

Another object is to provide in such a tuner means for setting eachbutton of the tuner for a desired station without disassembling anyparts of the set.

Still another object is to provide a tuner of the type described abovewhich can be used in connection with a receiving set having a manualtuning dial particularly of the projector type wherein the tuner is inthe form of a ring which surrounds the dial.

These and other objects as will hereinafter appear are accomplished bythis invention which is fully described in the following specificationand shown in the accompanying drawings in which:

Figure 1 is a partial front elevation of a chassis removed from itscabinet showing one embodiment of the invention with an operators handin position to tune the set to a given station;

Fig. 2 is a similar view of the tuner only after it has been turned tothe desired station;

Fig. 3 is a partial top plan of the chassis;

Fig. 4 is a partial enlarged section on the line 4-4 of Fig. 3 showingthe front mounting plate removed together with the automatic tuningmechanism;

Fig. 5 is a partial enlarged section as viewed on the line 55 of Fig. 3;

Fig. 6 is an enlarged vertical elevation on the broken line 5-6 of Fig.1;

Fig. 7 is a section on the broken line ll of Fig. 6 showing one of thetuning fingers between the vertical stops in the act of tuning the setwith the automatic tuner;

Fig. 8 'is a similar view showing the end stop which prevents rotationof the tuner below a predetermined point;

Fig. 9 is an enlarged section on the line 9--9 of Fig. 6;

Fig. 10 is a partial perspective of a portion of the automatic tuningdial showing a button and its tab in their normal inoperative positions;

Fig. 11 is the same showing the button depressed and the tab rotatedabout the axis of the button to a releasing position;

Fig. 12 is a view of the parts showing the button further depressed soas to permit of adjustment of the button and its associated tuningfinger for a given broadcasting station;

Fig. 13 is a partial section on the line l3 of Fig. 2 showing the buttondepressed in the operation of tuning the set;

Fig. 14 is'a partial section on the Fig. 12;

Fig. 15 is an enlarged section on the line 15-! 5 of Fig. 13 showing thetab'in the position of Fig. 10;

Fig. 16 is a similar section showing the tab in the position of Fig.'11;

Fig. 17 is a similar section on the line l'l-ll of Fig. 14; I

Fig. 18 is a partial enlarged section on the line [8 of Fig. 5 showingthe limit stop in adjusted position; and

Fig. 19 is the same in process of being adjusted.

The embodiment illustrated shows a set having the usual manual means foradjustment over its entire range together with a means for quickly andaccurately tuning the set for a number of stations whose positions havebeen predetermined.

Briefly the set may be tuned in the usual way by hand by rotating a gangcondenser A (Fig. 3), the stations tuned beingshown on a ground glassscreen by light from a dial lamp B which projects light through aphotographic film C'on a mirror D which reflects the image on agroundglass dial E which is viewed by the operator. This forms no part of thepresent invention and hence will not be described in detail.

The automatic tuner is mounted to rotate about the dial E and isdesigned to quickly and accurately tune in any one of a number ofpreviously selected stations whose positions have previously beenlocated on the automatic tuner and a button therefor set on the tuner aswill hereinafter be explained. i

The chassis as illustrated comprises a main frame 29 which is pressedfrom sheet metal and on which is yieldingly mounted a plate 2| (Figs. 4and 6) by means of rubber buffers 2| to which is secured a casting 22which has a tubular extension 23 through which passes light from themirror D on its way to the screen E. This screen is enclosed in a rubbergasket 24 which is held in place by means of an annular finishing strip25 which is retained by screws 26.

A front mounting plate 21 is secured to the plate Zl by means of screws28 and to the casting 22 by means of a screw 29. This front mountingplate carries most of the parts which go to make up the presentautomatic tuner. This tuner comprises among other things a ring gear 30,a tun ing ring 3! which has bosses 3W by means of which it is secured tothe ring gear by means of line i l-44 of screws 31*, and a. drum 32which is secured to bosses on the ring gear by means of screws 30*.

The ring gear 30 (Fig. 5) is mounted on four grooved rollers 33 each ofwhich is rotatably mounted on a screw 34 afiixed to the front mountingplate. The ring gear rests upon the grooved rollers and is guided by theupper two, the ring gear having gear teeth of reduced width which passthrough a groove in the rollers as shown in Fig. 6.

A substantially non-extensible flexible cord 35 passes substantially oneand one-half times around the drum. 32 and has one end secured theretoby means of a short spring 36 (Fig. 5) while the other end is securedthereto by means of a relatively long spring 31, the latter particularlytending to maintain the cord under a uniform tension at all times. Thiscord passes around a grooved tuning spool 38 which is keyed on a shaft39 which is suitably journaled preferably in a ball-bearing housing 40carried by the front mounting plate 21. The cord 35 may also pass overan idler 4|.

The ring gear 30 meshes with a gear 42 which drives a pinion 43 whichmeshes with a gear 44 which acts through a sleeve 44 to drive an arm 45which has an extension 45 which is adapted to lie between a lug 46 and ashort leaf spring 41 (Figs. 5, 6 and 9). 6 and 9, the lug 46 and thespring 41 are carried by sheaves 48 on the shaft 49 of the gangcondenser A. The sleeve 44 is rotatable about a stud 44 which is carriedby the front mounting plate 21 and is in alignment with the shaft 49.This provides a convenient flexible drive to the gang condenser whichpermits the front mounting plate to be removed. Upon reassembling, theextension 45 is readily inserted between the lug 46 and the spring 41,when these parts are in proper alignment.

Thus it will be seen that the set is manually tuned by rotating theshaft 39 by means of the tuning knob 39 (Fig. 1). At the same time, thephotographic film C is rotated in front of the dial lamp B by means of awire rope (Fig. 4') which passes around a drum 5! on a shaft 52 whichcarries the film C and which is tensioned by means of an idler sheave 53carried on a lever 54 under the action of a spring 55.

The automatic tuning feature will now be described. The purpose of thisis to enable the operator by a single movement of his hand to bring thetuning dial 3! to rest at the exact point at which it is in tune for agiven station. To do this we have provided the tuning dial with aplurality of buttons 56, which are located at intervals in the tuningdial 3|, each to be marked with a suitable disk 51 with the call lettersof a station which it is desired to tune with that button, the diskbeing covered by means of a transparent cover 58 of Celluloid or thelike.

Each button is in alignment with the shaft of a tuning element 59 whichis rotatably mounted in a boss 60 on the ring gear 30, there being anextension 59* passing through the button to which it is keyed and towhich it is secured by means of a spring clip 6| engaging within anannular groove in the extension. A spring 62 serves to hold the buttonnormally in the outer position, as shown in Fig. 6.

The tuning element 59 has at its opposite end a lever 63' whichterminates in a cylindrical tuning finger 64. Each tuning element 59carries a locking arm 65 the outer surface of which is As will be seenfrom Figs.

serrated while an inner arcuate surface 66 (Fig. 5) is provided withcomplementary serrations so that each lever arm 63 is capable ofadjustment through quite a wide range and of being secured in any ofthose adjusted positions by the engaging serrations. Inasmuch as thepoint at which the tuning dial will stop depends upon the position ofthe finger 64, it will thus be seen that each one of the tuning elementsis capable of stopping the dial at many points.

Referring now to Fig. 6, it will be seen that the button 56 and itsassociated tuning element 59 are normally maintained in an out positionby means of the spring 62. To bring a particular element into operation,the operator pushes in the button and then swings the tuning dial so asto bring this button to the lowermost position. As he does so the finger64 encounters a stop which will now be described. The stop is shown inFig. 7 and consists of two opposing yielding stop blades 61, 68 whichare rotatably mounted on pins 69, 2'0 at the bottom and top respectively(Figs. 6 and 7) and are yieldably urged toward each other by means of aspring H so that they normally rest against lugs 61*, 68 The distancebetween the blades 61 and 68 is but slightly greater than the diameterof the cylindrical finger 64 and the sides of these blades which areencountered by the finger 64 when depressed are inclined in bothdirections so that no matter from which direction the finger proceedstoward these blades, it depresses the first one and is stopped by theother, the first blade then promptly springing into place behind thefinger, as shown in Fig. '7. If, therefore, the tuning element 59 hasbeen accurately set for the reception of a given broadcasting station,that station will be received the instant the tuning dial is turned soas to bring the tuning finger of that tuning element between the stopblades 61, 68.

As long as the button remains depressed with one of the fingers 64between the blades of the stop, the set cannot be tuned by means of thetuning knob 39. Also, for reasons which will later be described, the setis completely detuned as long as the button 56 remains depressed.

An adjustable stop for the tuning dial is provided by the stop member 12(Figs. 5, 8, 18 and 19) which is eccentrically mounted upon a shaft 13which passes through the ring gear 30 and has an extension 74 the edgeof which is serrated for engagement with the serrated edge of theopening 15. The member 12 is normally held retracted in the positionshown in Fig. 18' by means of a spring 16. This stop member 72 is longerthan the fingers 64 so that it engages the stop blade 61 as it reachesthe end of the swing of the dial in one direction and engages the stopblade 68 when it reaches the end of its swing in the reverse direction.This stop member is set once and need not be reset. This stop memberlies immediately back of a wide spacer 11 (see Fig. 1) which at itslowest point comes to the end of the swing of the tuning dial in eitherdirection, and thus corresponds to a wave length oftthe highest or thelowest permissible by the se a With none of the buttons 56 depressed theset can be tuned by hand in the usual way. It is desirable, however,that while using the automatic tuner the set shall be inoperative sothat it will not pick up the stations through which it passes beforereaching the desired station. In order to do this we have added a metalring 18 (Fig. 13) which is secured to the back of the tuning dial 3| butinsulated therefrom. A brush 19 which is insulated by insulation I9 fromthe front mounting plate 21 is connected through a suitable insulatedlead 80 with a portion of the tuning circuit, not shown. Each buttoncarries a metal member 8! which is keyed thereto and rotatably heldthereon by a collar 56 which is cemented in place. The metal member 8|has a tab 82 which in the position shown in Fig. 10 is thrown to theleft. The member 8| extends down so that when the button isdepressed'for the purpose of tuning as shown in Fig. 13, the member 8|makes contact with the ring 18 with the result that the tuned circuit isthen grounded through the member 8|, the spring 62 and the ring gear 30.It will thus be seen that a convenient method is thus provided forsilencing the set during the time the button 56 is depressed.

The method of adjusting each tuning element will now be described. Thisis shown in Figs. 10 to 17, inclusive. The tab 82 normally remains atthe left hand side as shown in Fig. 10. The member 8i engages the ring18 and hence prevents the member 56 from. being depressed far enough topermit the locking arm 65 to pass out of engagement with the toothedarcuate portion 66, and consequently, the tuning finger 64 remains fixedwith respect to the tuning dial. During the operation of setting eachtuning finger S4 for a given station, it is necessary that the arm 65 bepermitted to swing freely until the desired setting is reached afterwhich this arm will then become locked with the serrated arcuate portion66. In order to do this the tab 82 swings about the axes of the button56 and the element 59, as shown in Fig. 11. This permits the inner endof the member 8| to pass the inner edge of the ring I8 with the resultthat when the button is now depressed, as shown in Fig. 14, the set willnot be shorted but will continue to play if a station is tuned in. Atthe same time, the button 56 is permitted to be further depressed as isalso the element 59, thereby freeing the arm 65 from the serratedarcuate portion 66.

If with the parts in the position shown in Fig. 14 the finger is heldbetween the stop blades 61, 68, as shown in full lines in Fig. '7, theset can be tuned by hand by turning the tuning knob 39* (Fig. 1) untilthat particular station is sharply tuned in. The operator then releasesthe button and the spring will return the element 59 to its normalposition in which the arm 65 will be locked by the serrated arcuateportion 66. This button is then permanently locked in this position byholding the button in the position shown in Fig. 11 which is amid-position during which time the tab 82 can be moved from the fullline position of Fig. 11 to the dotted line position. The tab isprovided with a small depression into which the operator may place apencil or other sharp object which serves to swingthe tab from oneposition to the other. In moving the tab from the dotted line positionto the full line position, the button must also be held in theintermediate position of Fig, 11.

operator also selects a disk 5'! showing the call letters of thatstation and places it in the button as shown in Fig. 6 with atnansparent cover 58. This provides a smooth surface for the operator'sfinger during the operation of tuning and keeps the disk 58 frombecoming soiled.

Thus it will be seen that a very simple and eificient means is providedfor tuning in a given broadcasting station by a simple continuousmovement of the operator's finger. While we have shown and described buta single embodimentof this invention, it is to be understood that it iscapable of many modifications. Changes, therefore, in the constructionand arrangement may be made which do not depart from the spirit andscope of the invention as disclosed in the appended claims.

' We claim:

1. In a radio receiving set, a chassis frame, a front plate of shallowdepth removably carried thereby, a rotatable tuning condenser carried bythe chassis frame, and means carried by the plate and removabletherewith for tuning the condenser, said means having a flexible drivingconnection to the condenser which is readily separable from thecondenser on removing the front plate from the chassis frame, saiddriving means including spaced driving members on one element, one ofwhich is yieldable and a tongue on the other element adapted to liebetween the spaced members.

2. In a radio receiving set, a radio tuning element, a dialing memberrotatably mounted in the set, a stop, a plurality of buttons yieldablycarried by the dialing member, each button being adapted to be depressedby an operator and having a finger adapted to engage the stop only whenthe button is depressed to stop the rotation of the dialing member, saidfinger being eccentric to the axis of the button, each button beingrotatable about its axis when depressed beyond a given point topermit'the dialing member to be turned to tune in a desired stationwithin the limits of movement of the finger, and means for locking thebutton which in one position prevents the button from being depressedfar enough to be rotated into another adjusted position and in anotherposition permits the button to be depressed for this purpose.

3. In a radio receiving set, a radio tuning element, a dialing. memberrotatably mounted in the set, a stop, a plurality of buttons yieldablycarried by the dialing member, each button having a finger adapted toengage the stop only when the button is depressed to stop the rota tionof the dialing member, said finger being eccentric to the axis of thebutton, each button being rotatable about its axis to permit the dialingmember to be turned to tune in a desired station within the limits ofmovement of the finger, and means for locking each button so that itsfinger lies in any one of a number of adjusted positions, said meanscomprising a tab rotatably carried by each button, said tab when in anormal position preventing the depression of the button beyond apredetermined point and permitting its depression beyond said point forthe purpose of readjusting the setting of the finger when in anotherposition.

4. In a radio receiving set, a radio tuning element, a dialing memberrotatably mounted in the set, a stop, a plurality of buttons yieldablycarried by the dialing member, each button having a finger adapted toengage the stop only when the button is depressed to stop the rotationof the dialing member, said finger being eccentric to the axis of thebutton, each button being rotatable about its axis to permit the dialingmember to be turned to tune in a desired station within the limits ofmovement of the finger, and means for locking each button so that itsfinger lies in any one of a number of adjusted positions, said meanscomprising a tab rotatably carried by each button, said tab when in anormal position preventing the depression of the button beyond apredetermined point and permitting its depression beyond said point forthe purpose of readjusting the setting of the finger when in anotherposition, the button when depressed acting to silence the set when thetab is in the normal position but without silencing the set when the tabis in the other position.

5. In a radio receiving set, a radio tuning element, a dialing memberrotatably mounted in the set, a stop, a plurality of buttons yieldablycarried by the dialing member, each button having a finger adapted toengage the stop only when the button is depressed to stop the rotationof the dialing member, said finger being eccentric to the axis of thebutton, each button being rotatable about its axis to permit the dialingmember to be turned to tune in a desired station within the limits ofmovement of the finger, and means for locking each button so that itsfinger lies in any one or a number of adjusted positions, said meanscomprising a tab rotatably carried by each button, said tab when in anormal position preventing the depression of the button beyond apredetermined point and permitting its depression beyond said point forthe purpose of readjusting the setting of the finger when in anotherposition, said tab being of metal and making electrical contact with aportion of the set so as to silence the same when the tab is in a normalposition but not when the tab is rotated to the other position whereadjustment is permitted.

6. In a dial telephone type tuning control mechanism for radioreceivers, in combination, a casing mounted for rotation and operativelyconnected to a tuning element of said receiver, a multiplicity ofplungers arranged peripherally around said casing, and projectingtherethrough, said plungers terminating in fingers projecting inwardly,a pair of yieldable gates arranged to be entered by said fingers indepressed position only, to provide a positive stop against rotation ofsaid casing in either direction, one of said plungers normally biased toforward position and having a finger of greater length than the others,and of sufiicient length to abut against one of said gates when saidplunger is in forward position and of sufficient width to preventclosure of the other gate therebehind, whereby to form a stop limitingthe rotation of said casing to 360.

JESSE H. CLARK. ALBERT S. WELLS.

